From: Paolo Bonzini <pbonzini@redhat.com>
To: Pavel Fedin <p.fedin@samsung.com>,
kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: marc.zyngier@arm.com, 'Christoffer Dall' <christoffer.dall@linaro.org>
Subject: Re: [RFC] Handling CP15 timer without in-kernel irqchip
Date: Fri, 2 Oct 2015 11:30:44 +0200 [thread overview]
Message-ID: <560E4EC4.5050101@redhat.com> (raw)
In-Reply-To: <00a001d0fce3$f76e2170$e64a6450$@samsung.com>
On 02/10/2015 09:28, Pavel Fedin wrote:
> 2. Another possible approach, based on how device tree binding is handled by Linux. It is possible
> to remove virtual timer IRQ from the device tree, in this case the kernel reverts to using physical
> timer. When running under hypervisor, accesses to physical CP15 timer are trapped into HYP,
> therefore we can forward them to userspace using new exit code, something like KVM_EXIT_REG_ACCESS.
> In this case the timer would be also emulated by the userspace, which is slower, but allows better
> emulation. Also, this could be used in order to run some other guests which just expect physical
> timer to be there.
>
> Both approaches have their own limitations, but anyway this is much better than nothing. What do
> you think, and which approach do you like more?
I like the latter. But I guess one could even do both?
Paolo
next prev parent reply other threads:[~2015-10-02 9:30 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-02 7:28 [RFC] Handling CP15 timer without in-kernel irqchip Pavel Fedin
2015-10-02 9:30 ` Paolo Bonzini [this message]
2015-10-02 9:41 ` Pavel Fedin
2015-10-02 9:58 ` Peter Maydell
2015-10-02 10:05 ` Paolo Bonzini
2015-10-02 10:16 ` Peter Maydell
2015-10-02 10:18 ` Paolo Bonzini
2015-10-02 10:22 ` Pavel Fedin
2015-10-02 10:23 ` Peter Maydell
2015-10-02 10:18 ` Pavel Fedin
2015-10-02 10:22 ` Marc Zyngier
2015-10-02 10:33 ` Pavel Fedin
2015-10-02 14:54 ` Pavel Fedin
2015-10-02 20:26 ` Christoffer Dall
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